Is it worth getting fast flow nipples?

I would say that DS has about a month left of bottles. I phased out bottles at about 13 months with DD and I was planning on the same with DS. He is already good with a straw and decent with a sippy cup.
But I am also starting to totally wean him from BF, so we are going to be doing more bottles I think. I had actually started giving him 2-4 oz. of formula in a straw cup with breakfast, and he sucks it right up. But today I thought maybe a bottle would be better (for whatever reason) but he took forever to finish it. I'm wondering if I should just switch out the nipples to fast flow, now that he is almost done BF. Does the liquid really come out noticeably faster?
Or maybe we should just start doing cups for some feedings?

Well, we use the NUK bottles and there was a definite difference in the flow between the regular and the faster flow nipples. Ds didn't like the faster flow, even though he literally collapses the slow flow nipple.

I may have to try again though.

Maybe just buy one set and see? It's not a huge investment!